Microcirculatory dysfunction is an important pathophysiology mechanism of early brain injury after aneurysmal subarachnoid hemorrhage (aSAH), which contributes to poor outcomes. The study was performed in Beijing Tiantan Hospital from October 2020 to July 2023. Patients with aSAH who underwent computed tomographic perfusion (CTP) within 24 h after ictus were enrolled prospectively. The peak time of arterial inflow (PTA), peak time of venous outflow (PTV), total venous outflow time (TVT), and difference value of arteriovenous peak time (DV) were collected from the time-density curve of CTP. Primary outcome was 3-month unfavorable functional outcome (modified Rankin Scale score of 4-6). Secondary outcomes included 3-month all-cause death and delayed cerebral ischemia. Multivariable logistic regression analysis and restricted cubic splines were performed to explore the relationship between cerebral hemodynamic parameters and outcomes. We also assessed the prognostic performance of incorporating hemodynamic parameters into previous nomogram models for 3-month poor clinical outcomes. A total of 612 patients were enrolled, among whom the mean age was 56.9 ± 12.3 years old and 391 (63.9%) were female. On multivariable analysis, prolonged TVT could significantly predict 3-month poor functional outcome (adjusted OR 1.074, 95%CI 1.013-1.139), while prolonged PTA was an independent predictor of 3-month all-cause death (adjusted OR 1.293, 95%CI 1.099-1.521). The addition of TVT or PTA to previous nomogram models led to improvements in C-statistics, net reclassification (NRI), and integrated discrimination improvement (IDI). Our study underscores the vital role of arterial inflow and venous outflow in sustaining microcirculation during the acute phase after aSAH, thereby offering new directions for future investigations into therapeutic targets.